Desert Dreamin'

I know, I know, it's winter and I should be playing in the snow, but the desert was calling.

I had heard about the Gold Butte Backcountry Byway from my days living in Las Vegas. Details were sketchy and incomplete. All I could surmise was to expect a long dusty road out on the east side of Lake Mead linking a few odd and interesting things together, with miles and miles of good old Mojave-Desert emptiness in between. Sounded like the perfect place to explore by bike...After a 5 AM start and a 2 hour drive, I arrived at Whitney Pocket - one of several colorful isolated masses of upturned Navajo, err... I mean Aztec (since I was in Nevada) Sandstone. A closer look into the deep cracks and canyons of Whitney Pocket reveals some fine work by the CCC boys of the 1930s. This cleverly designed reservoir captures water and delivers it to a nearby stock tank - still works like a charm some 70 years later.Above: a shady and cool food storage cave next to the historic CCC camp.Blazing 8 miles or so down the Gold Butte Road brought me to the head-scratching geologic phenomenon known as Devil's Throat. This is one impressive sinkhole (that's still growing), but the puzzling thing is that sinkholes typically form in wet areas with lots of limestone bedrock. But here we are in the middle of the desert and no bedrock at all - just a seemingly infinite column of alluvial fan material being swallowed into a deep unseen cavern.Looking over the edge of Devil's Throat.Heading west from Devil's Throat, the rough Jeep road devolves into a faint path in a wash bottom. I soon encountered more red Aztec Sandstone with a nice desert varnish - a perfect medium to depict that sheep hunt, the location of a cool spring, an alien encounter, or whatever.After slogging several miles through the wash, I came upon one of the most unique places I've ever been to. I guess it's similar to Goblin Valley but the portly goblins, rounded toadstools, and bulbous mushrooms of Goblin Valley contrast greatly to the razor-edged dragons, piles of shattered glass, and knife-wielding warriors of this place, known to some as "Little Finland."Above: looking out the yawning mouth of a sleeping giant.This area would be the perfect laboratory for a geologist interested in differential erosion and the formation of tafoni (weather pitting) features.So what geologic processes have contributed to the formation of these erosional monsters? The answer is a normal fault. In the photo above you can see the pale orange Jurassic-age Aztec Sandstone on the left has been dropped down adjacent to a dark-red Triassic-age mudstone on the right. Normally, the down-dropped (or hanging wall) side of the fault sits topographically lower than the upthrown (or footwall) side of the fault. But here, the very strong and resistant Aztec Sandstone in the hanging wall sits much higher because the weak mudstone of the footwall has eroded away faster than movement on the fault can bring it up. So in short, this fault has created an elevated block of Aztec Sandstone and the edge of that block is eroding into some pretty amazing features.Above: looking north along the fault-edge block of eroding Aztec Sandstone.

Below: looking south along the fault. Faults often impede the lateral movement of groundwater, forcing water to the surface and creating springs. Here in the desert that spring water evaporates as soon as it reaches the surface, leaving behind the white minerals (mostly gypsum, salt, and calcium carbonate) that were in the water's solution. This small amount of water brought to the surface also has created an oasis in an otherwise bone-dry desert, with palm trees and even a couple of small hanging gardens. These springs were undoubtedly a critical resource for Native Americans. This is confirmed by the hundreds of petroglyphs found in the area.Above: a layer of minerals coat crossbeds of Aztec Sandstone near the fault.Like a clumsy guy in a fine china shop, a small miss-step and a bump could shatter what 100s of years of erosion have taken to create. These formations are extremely delicate.Do you remember being a kid and taking your little green plastic army men outside into the dirt and rocks, trying to imagine a full-scale world for them to battle in? Well, this would be the ultimate place for that. There are miniature mars-like landscapes here that would make the most imaginative Hollywood set producers envious.Taking a closer look and trying really hard not to break anything.Above: the large block of sandstone on the right has detached from the main cliff face along a joint.Above: a huge desert palm grows where it can draw water up out of fractured rock within the fault zone.Above: small crossbed of Aztec Sandstone, amazingly preserved, sticking 4 feet out in relief where the rest of the sandstone has eroded away.Interesting geology abounds everywhere you look out here. Above appears to be a massive thrust fault, most likely from the Cretaceous-age Sevier Orogeny (mountain building event). The blue and gray Paleozoic carbonate rocks on the left have been smashed up and over the younger red Aztec sandstone on the right.Above: a classic angular unconformity (gap in geologic time) with contorted maroon Triassic-age shale overlain by much younger alluvial (stream-derived) material.

Below: the Overton Arm of Lake Mead is visible the distance.The sandstone bluffs northeast of Black Butte and Bitter Ridge are dotted with petroglyphs of various ages and styles. I spent maybe an hour looking, and I'm guessing I just barely scratched the surface.Above: snake-like petroglyphs line a window that overlooks a sea of petrified sand dunes that glow in the evening sun.At the end of the day, I had biked about 32 miles, many of them slow-going through soft sand. With a few miles of hiking and rock-scrambling, it all adds up to one very successful desert romp.